Greek historians wrote of an oracle at Delphi who provided cryptic consultation
to pilgrims plagued with questions. For about 12 centuries Delphic women chosen
for this job delivered the advice of the gods, from family matters to choosing
sides during times of war. During the late Bronze Age, around 1200 B.C., they
translated for the Earth goddess, Gaia, and later in the eighth century B.C.
spoke as Apollos vocal instrument when this god took over the sanctuary.

The oracle sat on a three-legged stool in the interior recesses of the temple,
calmly delivering her prose while inhaling the breath of the gods. This breath,
or pneuma, emanated from fissures in a floor left naked to the earth, according
to classical accounts. Springs bubbling to the surface, they said carried sweet-smelling
fumes. Some days and months were better for prophecy than others. The oracle
spoke specifically on the seventh day after each new moon, but not at all in
winter. If the temples visitor demanded a forced performance at the wrong
time, the oracle might run wild and frantic around the room delivering her prophecy
in a frenzy.

Throughout this time, the sacred site remained in a unique geological location.
According to a team of four researchers led by geologist Jelle de Boer of Wesleyan
University in Middletown, Conn., the temple was built over the intersection
of two faults: one young and active and the other old and probably inactive.
Since 1996, de Boer and colleagues in the fields of archaeology, chemistry and
toxicology have been exploring the implications of these faults. Embedded in
oily limestone, the faults vented hydrocarbon vapors through fissures in the
bedrock and continue to bubble forth ethylene, ethane and methane in neighboring
springs today.

All three hydrocarbon gases have the potential to produce an altered mental
state, says Henry Spiller of Poison Center at Kosair Childrens Hospital
in Louisville, Ky., who published a paper on the toxic aspects of these gases
in the April issue of Clinical Toxicology. Ethylene in particular would
have the strongest effect and is often described as a sweet-smelling gas. The
onset of the effects from ethylene are nearly immediate. The dose needed for
an awake euphoric feeling are significantly less than that needed for deep operable
anesthesia, Spiller says. During the first human experiments with ethylene
as an anesthetic gas in 1923, most subjects had a very pleasant experience.
However two people in the 12 studied had periods of excitement, confusion and
combative behavior, similar to a frantic oracle on a bad day.

The philosophers in the first century wrote of gases producing euphoria and
of a spring emanating from fissures, or chasms, in the bedrock inside the oracular
chamber. But a dichotomy arose in the 20th century between ancient and modern
interpretations for the geological source of the oracles inspiration.
In 1892 and following years, French archaeologists including Pierre Amandry
excavated the temple ruins and were disappointed to find fissures and water,
but not the opening of a chasm. In 1904 a visiting English scholar A. P. Oppé
deemed the ancients were perpetuating a myth or worse a blatant lie. He stated
that Delphi did not sit on volcanic land and therefore the bedrock never emitted
gases. Amandry in 1950 published a book also declaring the area volcano- and
vapor-free. Over the decades the original French finding of water and fissures
was forgotten and the Greek interpretations ignored. In their place came a standing
assumption that the ancients were wrong.

Geological features
beyond the immediate temple site provided more modern explanations on how the
myth got started. The sanctuary of Apollo sits at the base of Mount Parnassus,
where faults crisscross the region like wrinkles in the palm of an aged hand.
Motion along the Delphi fault, which strikes east-west under the sanctuary,
is thought to have caused the destruction of Apollos older temple in 373
B.C. But ruins and landslide deposits obscure the exact site where the fault
runs below the temple. Questions arose concerning the role of this fault in
the rise of the mysterious vapors.

Wesleyan University graduate student Emily
Hager stands beside the exposed face of the Kerna fault. Photo courtesy of John
Hale.

Archaeologist John Hale of the University of Louisville in Kentucky took some
cajoling from de Boer to begin what would become a five-year expedition to determine
the veracity of the ancient accounts. Over a bottle of Dão, a Portuguese
red wine, the two made a bet. Jelle de Boer caught my interest with his
description of exposed fault planes that he had seen on the slope of Mount Parnassus
east and west of the oracle site, and with his assumption that this fault represented
the chasm in the earth that ancient authors linked to the Delphic oracle,
Hale says. It took a bet or a challenge to start this project because
for almost a century it has been an article of faith among archaeologists, historians
and classicists that the ancient traditions about the Delphic oracle were all
wrong. I was very reluctant to admit that a geologist might be able to prove
that it was modern scholarship that was wrong, and the ancient authors were
right.

Last year in the August issue of Geology, de Boer and his team reported
the discovery of a second fault they called Kerna, after a spring northwest
of Apollos temple, and the gaseous findings of the spring. The Kerna and
Delphi fault zones contain numerous extensional fissures, de Boer says. Where
the faults intersect the bedrock is especially permeable. With regard
to the absence of volcanic fumes, de Boer says: Fractures all over the
world emit gases. Here in New England, for instance, radon surfaces along faults
in many areas. Along the fractures in Delphi, warm groundwater significantly
enriched in calcium has emerged for ages. The springs left deposits of
travertine below the temple and among the ruins. Geochemist Jeffrey Chanton
of Florida State University found methane and ethane still trapped in the travertine.
The ethylene, a less stable molecule, he found still emerging from Kerna spring,
but not in a spring 100 meters to the east of the temple. This finding
suggests that the sites of hydrocarbon emissions at Delphi vary in output and
are rather localized, the authors say.

Delphi is not the only Greek site where hydrocarbon gases emerge. On the island
of Zakynthos to the west, where gas springs and tar pits are tourist attractions,
Chanton found spring water with ethylene levels similar to those in Delphi.

Now de Boer and his team have opened the flood gates for further research to
investigate the truth of the ancient accounts. It is interesting to note
that the Delphi oracle never held sessions during the winter months, when the
god Apollo was believed to have gone north to the land of the Hyperboreans.
de Boer says. This suggests that the gas emissions at Delphi may have
diminished during the colder periods.

Geologist George Davis of the University of Arizona runs a seminar that integrates
geology and archaeaology. In January, Hale was one of his guest lecturers. Im
confident if someone would go with Hale to that site, they would be convinced
that at least one fault passes right through the site and that gases have been
measured coming out of the fault zone that would have affected people, including
the oracle, in the enclosed chamber above the fault, Davis says. More
interpretive challenges of what may have happened still exist, but overall their
story holds together.